// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "content/browser/renderer_host/pepper/pepper_browser_font_singleton_host.h"

#include <stddef.h>
#include <stdint.h>

#include "base/macros.h"
#include "base/threading/sequenced_worker_pool.h"
#include "base/values.h"
#include "content/common/font_list.h"
#include "content/public/browser/browser_ppapi_host.h"
#include "content/public/browser/browser_thread.h"
#include "ppapi/host/dispatch_host_message.h"
#include "ppapi/host/resource_message_filter.h"
#include "ppapi/proxy/ppapi_messages.h"

namespace content {

namespace {

    // Handles the font list request on the blocking pool.
    class FontMessageFilter : public ppapi::host::ResourceMessageFilter {
    public:
        FontMessageFilter();

        // ppapi::host::ResourceMessageFilter implementation.
        scoped_refptr<base::TaskRunner> OverrideTaskRunnerForMessage(
            const IPC::Message& msg) override;
        int32_t OnResourceMessageReceived(
            const IPC::Message& msg,
            ppapi::host::HostMessageContext* context) override;

    private:
        ~FontMessageFilter() override;

        // Message handler.
        int32_t OnHostMsgGetFontFamilies(ppapi::host::HostMessageContext* context);

        DISALLOW_COPY_AND_ASSIGN(FontMessageFilter);
    };

    FontMessageFilter::FontMessageFilter() { }

    FontMessageFilter::~FontMessageFilter() { }

    scoped_refptr<base::TaskRunner> FontMessageFilter::OverrideTaskRunnerForMessage(
        const IPC::Message& msg)
    {
        // Use the blocking pool to get the font list (currently the only message)
        // Since getting the font list is non-threadsafe on Linux (for versions of
        // Pango predating 2013), use a sequenced task runner.
        base::SequencedWorkerPool* pool = BrowserThread::GetBlockingPool();
        return pool->GetSequencedTaskRunner(
            pool->GetNamedSequenceToken(kFontListSequenceToken));
    }

    int32_t FontMessageFilter::OnResourceMessageReceived(
        const IPC::Message& msg,
        ppapi::host::HostMessageContext* context)
    {
        PPAPI_BEGIN_MESSAGE_MAP(FontMessageFilter, msg)
        PPAPI_DISPATCH_HOST_RESOURCE_CALL_0(
            PpapiHostMsg_BrowserFontSingleton_GetFontFamilies,
            OnHostMsgGetFontFamilies)
        PPAPI_END_MESSAGE_MAP()
        return PP_ERROR_FAILED;
    }

    int32_t FontMessageFilter::OnHostMsgGetFontFamilies(
        ppapi::host::HostMessageContext* context)
    {
        // OK to use "slow blocking" version since we're on the blocking pool.
        std::unique_ptr<base::ListValue> list(GetFontList_SlowBlocking());

        std::string output;
        for (size_t i = 0; i < list->GetSize(); i++) {
            base::ListValue* cur_font;
            if (!list->GetList(i, &cur_font))
                continue;

            // Each entry is actually a list of (font name, localized name).
            // We only care about the regular name.
            std::string font_name;
            if (!cur_font->GetString(0, &font_name))
                continue;

            // Font names are separated with nulls. We also want an explicit null at
            // the end of the string (Pepper strings aren't null terminated so since
            // we specify there will be a null, it should actually be in the string).
            output.append(font_name);
            output.push_back(0);
        }

        context->reply_msg = PpapiPluginMsg_BrowserFontSingleton_GetFontFamiliesReply(output);
        return PP_OK;
    }

} // namespace

PepperBrowserFontSingletonHost::PepperBrowserFontSingletonHost(
    BrowserPpapiHost* host,
    PP_Instance instance,
    PP_Resource resource)
    : ResourceHost(host->GetPpapiHost(), instance, resource)
{
    AddFilter(scoped_refptr<ppapi::host::ResourceMessageFilter>(
        new FontMessageFilter()));
}

PepperBrowserFontSingletonHost::~PepperBrowserFontSingletonHost() { }

} // namespace content
